Ozest have the outside bundle cleaner XL. This system was developed in cooperation with several high pressure cleaning specialists in order to bring you a safe and efficient cleaning machine to clean the outside of your bundles fast, safe and easy.
The tube bundle is placed on two optional heavy duty rollers, which can be controlled from the cabin of the operator. The bundles are being cleaned by means of a horizontally driven nozzle bar, which can also move vertically and towards the bundle to get the best cleaning results. The right combination of water pressure (up to an optional 1500 bar) and flow, removes scaling, coke, polymers, etc. without the use of any additional cleaning materials.
The outside bundle cleaner XL has a horizontal stroke of 11 metres and the maximum height is 2.70 metres. The speed is adjustable from the cabin from 0-1 m/sec in order to get the best cleaning results.
All hydraulic controls are placed in the cabin where the operator can sit comfortably and safely without being exposed to the dirt coming back from the bundle. The power pack is situated behind the cabin, easily accessible and all hydraulic hoses are fitted with quick connectors for easy transportation.
As an machine can handle a lot more water to clean in between the tubes, the bundle can be cleaned all the way up to the centre and the risks for accidents is down to a minimum.
Safety
Because the operator can only operate the unit from the cabin, he is well protected from any dirt or high pressure water exiting from the tubes. An emergency shut off valve is also fitted in the cabin and the whole assembly has been build according to the latest CE regulations. All hydraulic cylinders and motors are fitted with safety valves.
Efficiency
Because of the variable speed control and the possibility to control all movements from the cabin, the outside bundle cleaner is a simple and effective machine, witch will prove to be also very cost effective. The unit can easily be dismantled into 3 pieces for easier transportation and in order to save space. The unit is completely equipped with quick connectors for easy removal of all hydraulic hoses.
Wednesday, August 20, 2008
Inside Bundle Cleaner IBC-5
In order to meet the demands of high pressure cleaning contractors, Ozest haveInside Bundle Cleaner. The IBC 5 is one of the fastest cleaning machines in the world today and has been designed to clean a large number of bundles on the cleaning slab, during shutdowns.
Our goal was to design a machine which can be fully operated from inside the cabin by 1 operator, in a very simple and efficient way. From the cabin, the operator can control the up/down/left/right movement with a simple joystick, the rollers can be turned, the outriggers can be operated and the lancebed can be moved forward and backwards ± 60 cm. The lancebed has been created out of 10 meter long T-bars, which give a perfect guide for the lances and at the same time avoid dirt from remaining in the lancebed.
Adjustment of the pitch is done by tightening nuts, which keeps the pitch fixed at all times and because the lance bed and the pitch are not covered, it is very clear to see for the operator if his lances are in the right position. The chains, which drive the lances, are located in a tray with a Teflon liner to avoid damage to the metal and the chain is being tensioned by a tandem construction, which avoids the chain from slapping against the metal.
The length of the lances which move into the tubes can be set by using sensors, to prevent lances from damaging and entering too far. Especially in cases with hairpin bundles, this can be very effective. At the same time, the hydraulic power to move the lances forward can be adjusted, to prevent the lances from breaking in case of a blockage. In case there is a problem with a hose or a lance, they can be replaced in a matter of minutes by removing the guide pieces at the front.
Safety
In order to make the machine as safe as possible, we have made 2 standard emergency stops on the machine, 1 inside the cabin and 1 outside at the backside. If you enter with the lances inside a tube, all other hydraulic controls will be blocked. The cabin will lock itself at any height when there is a hydraulic failure during lifting/lowering. The machine has been build according to the latest CE regulations.
Efficiency
Due to the weight of the machine and its speed of the lances, it is a very stable and fast machine which has enough power to clean bundles very fast and therefore cost effective. All controls are located inside the cabin, next to the operator, to create an unobstructed view and comfortable working position.
Aerial Tube Bundle Extractor
A fast, safe and self contained unit to deal with all your bundle extracting problems.
Ozesthave Aerial Tube Bundle Extractor is a self contained unit, which is easily lifted into position by just one crane and can be operated by remote control. Because the unit is equipped with a small diesel engine, it can work independently at any place. The Extractor is standard equipped with a spark arrestor and it can even be equipped with a chalwin valve to make it possible to work even in dangerous areas.
The standard extractor is 8.00m in length and weighs 8,5T. It is suitable for use on all plate and tube heat exchangers up to 2.00m diameter and a maximum bundle weight of 40T. In case you might need a bigger or a smaller extractor, Peinemann can also make custom made extractors to suit your needs.
The Aerial Tube Bundle Extractor uses a special lifting frame, which is constructed in such a way that it has a maximum reach into the construction. The load is trimmed using a Aerial balancing cylinder which makes it also easy to off load the bundles when the extractor is put down on the ground. Due to the use of a pulling hook mechanism and 2 butt plates which are clamped against the extractor’s shell, the massive power of 50.000kgf is compensated against the shell flange and not against the structure. With over 10 years of experience in the field of bundle extracting, you can always count on ozest as your partner.
Monday, August 18, 2008
CORROSSION INHIBITOR
Corrossion inhibitor has got a very important role in chemical cleaning. A corrosion inhibitor is a chemical compound that, when added to a fluid or gas, decreases the corrosion rate of a metal or an alloy.
The effectiveness, or corrosion inhibition efficiency, of a corrosion inhibitor is a function of many factors like: fluid composition, quantity of water, flow regime.... If the correct inhibitor and quantity is selected then is possible to achieve high, 90-99%, efficiency, but this higher values shall be documented by laboratory and field test. Some of the mechanisms of its effect are formation of a passivation layer (a thin film on the surface of the material that stops access of the corrosive substance to the metal), inhibiting either the oxidation or reduction part of the redox corrosion system (anodic and cathodic inhibitors), or scavenging the dissolved oxygen.
Some corrosion inhibitors are hexamine, phenylenediamine, dimethylethanolamine, sodium nitrite, cinnamaldehyde, condensation products of aldehydes and amines (imines), chromates, nitrites, phosphates, hydrazine, ascorbic acid, and others. The suitability of any given chemical for a task in hand depends on many factors, from the material of the system they have to act in, to the nature of the substances they are added into and their operating temperature.
An example of an anodic inhibitor is chromate which forms a passivation layer on aluminum and steel surfaces which prevents the oxidation of the metal. Unfortunately, chromate is carcinogenic in humans; the toxicity of chromates was featured in the film Erin Brockovich. Like hydrazine, the use of chromate to protect metal surfaces has been limited; for instance it is banned from some products.
Nitrite is another anodic inhibitor. If anodic inhibitors are used at too low concentration, they can actually aggravate pitting corrosion, as they form a nonuniform layer with local anodes.
An example of a cathodic inhibitor is zinc oxide, which retards the corrosion by inhibiting the reduction of water to hydrogen gas. As every oxidation requires a reduction to occur at the same time it slows the oxidation of the metal. As an alternative to the reduction of water to form hydrogen, oxygen or nitrate can be reduced. If oxidants such as oxygen are excluded, the rate of the corrosion can be controlled by the rate of water reduction; this is the case in a closed recirculating domestic central heating system, where the water in the radiators soon becomes anaerobic. This is a very different situation to the corrosion in a car door where the water is aerobic. For instance, cars suffer from the fact that water can enter the cavity inside the door and become trapped there. The fact that the oxygen concentration is not uniform within the layer of water in the door then creates a differental aeration cell leading to corrosion. A cathodic inhibitor would be of little use in such a situation as even after inhibiting the reduction of water, the reduction of dioxygen would still be able to occur. A better method of preventing corrosion in the car door would be to improve the design to prevent water being trapped in the door and to consider using an anodic inhibitor such as phosphate.
One very good example of a cathodic inhibitor is a volatile amine present in steam; these are used in the boilers used to drive turbines to protect the pipework in which the condensed water passes. Here the amine is moved by the steam in a steam distillation to the remote pipework. The amine increases the pH thereby making proton reduction less favorable. It is also possible that with correct choice, the amine can form a protective film on the steel surface and, at the same time, act as an anodic inhibitor. An inhibitor that acts both in a cathodic and anodic manner is termed a mixed inhibitor. Hydrazine and ascorbic acid (vitamin C) both help reduce the rate of corrosion in boilers by removing the dissolved oxygen from the water. However, as hydrazine is a highly toxic carcinogen, its use is being discouraged.
Antiseptics are used to counter microbial corrosion. Benzalkonium chloride is commonly used in oil field industry.
Corrosion inhibitors are commonly added to coolants, fuels, hydraulic fluids, boiler water, engine oil, and many other fluids used in industry.
For fuels, various corrosion inhibitors can be used
DCI-4A, widely used in commercial and military jet fuels, acts also as a lubricity additive. Can be also used for gasolines and other distillate fuels.
DCI-6A, for motor gasoline and distillate fuels, and for U.S. military fuels
DCI-11, for alcohols and gasolines containing oxygenates
DCI-28, for very low-pH alcohols and gasolines containing oxygenates
DCI-30, for gasoline and distillate fuels, excellent for pipeline transfers and storage, caustic-resistant
DMA-4 (solution of alkylaminophosphate in kerosene), for petroleum distillates
Corrosion inhibitors are often added to paints. A pigment with anticorrosive properties is zinc phosphate. Compounds derived from tannic acid (e.g. Kelate) or zinc salts of organonitrogens (e.g. Alcophor 827) can be used together with anticorrosive pigments. Other corrosion inhibitors are Anticor 70, Albaex, Ferrophos, and Molywhite MZAP.
and in chemical cleaning Rodine, Armohib, HAI, Nevamine are used according to chemicals and their concentration.
The effectiveness, or corrosion inhibition efficiency, of a corrosion inhibitor is a function of many factors like: fluid composition, quantity of water, flow regime.... If the correct inhibitor and quantity is selected then is possible to achieve high, 90-99%, efficiency, but this higher values shall be documented by laboratory and field test. Some of the mechanisms of its effect are formation of a passivation layer (a thin film on the surface of the material that stops access of the corrosive substance to the metal), inhibiting either the oxidation or reduction part of the redox corrosion system (anodic and cathodic inhibitors), or scavenging the dissolved oxygen.
Some corrosion inhibitors are hexamine, phenylenediamine, dimethylethanolamine, sodium nitrite, cinnamaldehyde, condensation products of aldehydes and amines (imines), chromates, nitrites, phosphates, hydrazine, ascorbic acid, and others. The suitability of any given chemical for a task in hand depends on many factors, from the material of the system they have to act in, to the nature of the substances they are added into and their operating temperature.
An example of an anodic inhibitor is chromate which forms a passivation layer on aluminum and steel surfaces which prevents the oxidation of the metal. Unfortunately, chromate is carcinogenic in humans; the toxicity of chromates was featured in the film Erin Brockovich. Like hydrazine, the use of chromate to protect metal surfaces has been limited; for instance it is banned from some products.
Nitrite is another anodic inhibitor. If anodic inhibitors are used at too low concentration, they can actually aggravate pitting corrosion, as they form a nonuniform layer with local anodes.
An example of a cathodic inhibitor is zinc oxide, which retards the corrosion by inhibiting the reduction of water to hydrogen gas. As every oxidation requires a reduction to occur at the same time it slows the oxidation of the metal. As an alternative to the reduction of water to form hydrogen, oxygen or nitrate can be reduced. If oxidants such as oxygen are excluded, the rate of the corrosion can be controlled by the rate of water reduction; this is the case in a closed recirculating domestic central heating system, where the water in the radiators soon becomes anaerobic. This is a very different situation to the corrosion in a car door where the water is aerobic. For instance, cars suffer from the fact that water can enter the cavity inside the door and become trapped there. The fact that the oxygen concentration is not uniform within the layer of water in the door then creates a differental aeration cell leading to corrosion. A cathodic inhibitor would be of little use in such a situation as even after inhibiting the reduction of water, the reduction of dioxygen would still be able to occur. A better method of preventing corrosion in the car door would be to improve the design to prevent water being trapped in the door and to consider using an anodic inhibitor such as phosphate.
One very good example of a cathodic inhibitor is a volatile amine present in steam; these are used in the boilers used to drive turbines to protect the pipework in which the condensed water passes. Here the amine is moved by the steam in a steam distillation to the remote pipework. The amine increases the pH thereby making proton reduction less favorable. It is also possible that with correct choice, the amine can form a protective film on the steel surface and, at the same time, act as an anodic inhibitor. An inhibitor that acts both in a cathodic and anodic manner is termed a mixed inhibitor. Hydrazine and ascorbic acid (vitamin C) both help reduce the rate of corrosion in boilers by removing the dissolved oxygen from the water. However, as hydrazine is a highly toxic carcinogen, its use is being discouraged.
Antiseptics are used to counter microbial corrosion. Benzalkonium chloride is commonly used in oil field industry.
Corrosion inhibitors are commonly added to coolants, fuels, hydraulic fluids, boiler water, engine oil, and many other fluids used in industry.
For fuels, various corrosion inhibitors can be used
DCI-4A, widely used in commercial and military jet fuels, acts also as a lubricity additive. Can be also used for gasolines and other distillate fuels.
DCI-6A, for motor gasoline and distillate fuels, and for U.S. military fuels
DCI-11, for alcohols and gasolines containing oxygenates
DCI-28, for very low-pH alcohols and gasolines containing oxygenates
DCI-30, for gasoline and distillate fuels, excellent for pipeline transfers and storage, caustic-resistant
DMA-4 (solution of alkylaminophosphate in kerosene), for petroleum distillates
Corrosion inhibitors are often added to paints. A pigment with anticorrosive properties is zinc phosphate. Compounds derived from tannic acid (e.g. Kelate) or zinc salts of organonitrogens (e.g. Alcophor 827) can be used together with anticorrosive pigments. Other corrosion inhibitors are Anticor 70, Albaex, Ferrophos, and Molywhite MZAP.
and in chemical cleaning Rodine, Armohib, HAI, Nevamine are used according to chemicals and their concentration.
Saturday, August 9, 2008
Passivation
Passivation is the process of making a material "passive" in relation to another material prior to using the materials together. For example, prior to storing hydrogen peroxide in an aluminium container, the container can be passivated by rinsing it with a dilute solution of nitric acid and peroxide alternating with deionized water. The nitric acid and peroxide oxidizes and dissolves any impurities on the inner surface of the container, and the deionized water rinses away the acid and oxidized impurities. Another typical passivation process of cleaning stainless steel tanks involves cleaning with NaOH and citric acid followed by nitric acid (up to 20% at 120F) and a complete water rinse. This process will restore the film, remove metal particles, dirt, and welding generated compounds (e.g. oxides).
In the context of corrosion, passivation is the spontaneous formation of a hard non-reactive surface film that inhibits further corrosion. This layer is usually an oxide or nitride that is a few atoms thick.
Passivation is a process performed to make a surface passive, i.e., a surface film is created that causes the surface to lose its chemical reactivity. Passivation unipotentializes the stainless steel with the oxygen absorbed by the metal surface, creating a monomolecular oxide film. Passivation can result in the very much-desired low corrosion rate of the metal.
It is seen that most of the fabricators are using the passivation solution for only the weld pool line or the heat dissipation areas. But that doesn’t ensures from risk of corrosion since the pitting on the remaining surface remain untreated as well as the corrosion susceptible gray zone remains forever. The simple spatters of the grinding also get indented into the surface and it causes the seeding for the corrosion. The chromium in the Stainless steel is playing anticorrosive roll in the play by forming the Cr2O3 Chromic Oxide. But it doesn’t guard against free ferrite on the surface.
With our passivation treatment on total area the there is hardly any corrosion susceptibility since all dirt is dissolved and the surface gets converted to the higher oxidation status as uniform film it becomes redundant to further corrosive attacks.
The passivation cost per square meter area is very less against the life and quality it ensures to the precision products.So we recommend always to go for total Passivation.
Mechanisms of passivation
Under normal conditions of pH and oxygen concentration, passivation is seen in such materials as aluminium, iron, zinc, magnesium, copper, stainless steel, titanium, and silicon. Ordinary steel can form a passivating layer in alkali environments, as rebar does in concrete. The conditions necessary for passivation are recorded in Pourbaix diagrams.
Some corrosion inhibitors help the formation of a passivation layer on the surface of the metals to which they are applied.
Electrochemical passivation processes
Some compounds, dissolving in solutions (chromates, molybdates) form non-reactive and low solubility films on metal surfaces.
Passivation of specific materials
Aluminium may be protected from oxidation by anodizing and/or allodizing (sometimes called Alodining), or any of an assortment of similar processes. In addition, stacked passivation techniques are often used for protecting aluminium. For example, chromating is often used as a sealant to a previously-anodized surface, to increase resistance to salt-water exposure of aluminium parts by nearly a factor of 2 versus simply relying on anodizing.
Iron based (ferrous) materials, including steel, may be somewhat protected by promoting oxidation ("rust") and then converting the oxidation to a metalophosphate by using phosphoric acid and further protected by surface coating. As the uncoated surface is water-soluble a preferred method is to form manganese or zinc compounds by a process commonly known as Parkerizing. Older, less-effective but chemically-similar electrochemical conversion coatings included bluing, also known as black oxide.
Nickel can be used for handling elemental fluorine, thanks to a passivation layer of nickel fluoride.
Terminology for assorted passivation processes
Bluing, also known as black oxide, and sometimes called browning when used in reference to historical processes dating from the 18th Century, is a passivation coating for the surfaces of iron and steel objects. It is one of the oldest passivation processes.
Newer, proprietary (and/or trademarked) processes for conversion coatings include Parkerized for passivating steel, dating to roughly 1912, and Alodine for passivating aluminium; both are trademarked processes and are now owned by Henkel Surface Technologies.
Chem film is any generic chromate conversion coating used to passivate aluminium. One such example is U.S. Patent 5,304,257. In general, however, chromate can also mean any of several chromate conversion coatings that can be applied to a much wider range of metals and alloys than just to aluminium. In recent years, chromate coatings have become less popular due to concerns over environmental pollution from using such processes.
Iridite is another trademarked name of a whole family of proprietary conversion coatings owned by MacDermid. A competing conversion coating used on aluminium, that somewhat ameliorates the environmental pollution concerns caused by chromate coatings, it often appears as a slightly yellowish coating, of roughly the same color as a yellow highlighting pen used to mark text on paper.
Rationale for passivating aluminium
Aluminium naturally forms an oxide almost immediately that protects it from further oxidation in many environments. This naturally-occurring oxide provides no protection during exposure to any saltwater spray environments, such as occurs in areas near bodies of saltwater. In such coastal environments, unprotected aluminium will turn white, corrode, and largely vanish over periods of exposure as short as a few years. The only way to prevent this from occurring is to use a more robust conversion coating on aluminium surfaces that will not be affected by the saltwater atmosphere. Alodine, Iridite, and chem film coatings can provide varying amounts of protection for aluminium surfaces.
In the context of corrosion, passivation is the spontaneous formation of a hard non-reactive surface film that inhibits further corrosion. This layer is usually an oxide or nitride that is a few atoms thick.
Passivation is a process performed to make a surface passive, i.e., a surface film is created that causes the surface to lose its chemical reactivity. Passivation unipotentializes the stainless steel with the oxygen absorbed by the metal surface, creating a monomolecular oxide film. Passivation can result in the very much-desired low corrosion rate of the metal.
It is seen that most of the fabricators are using the passivation solution for only the weld pool line or the heat dissipation areas. But that doesn’t ensures from risk of corrosion since the pitting on the remaining surface remain untreated as well as the corrosion susceptible gray zone remains forever. The simple spatters of the grinding also get indented into the surface and it causes the seeding for the corrosion. The chromium in the Stainless steel is playing anticorrosive roll in the play by forming the Cr2O3 Chromic Oxide. But it doesn’t guard against free ferrite on the surface.
With our passivation treatment on total area the there is hardly any corrosion susceptibility since all dirt is dissolved and the surface gets converted to the higher oxidation status as uniform film it becomes redundant to further corrosive attacks.
The passivation cost per square meter area is very less against the life and quality it ensures to the precision products.So we recommend always to go for total Passivation.
Mechanisms of passivation
Under normal conditions of pH and oxygen concentration, passivation is seen in such materials as aluminium, iron, zinc, magnesium, copper, stainless steel, titanium, and silicon. Ordinary steel can form a passivating layer in alkali environments, as rebar does in concrete. The conditions necessary for passivation are recorded in Pourbaix diagrams.
Some corrosion inhibitors help the formation of a passivation layer on the surface of the metals to which they are applied.
Electrochemical passivation processes
Some compounds, dissolving in solutions (chromates, molybdates) form non-reactive and low solubility films on metal surfaces.
Passivation of specific materials
Aluminium may be protected from oxidation by anodizing and/or allodizing (sometimes called Alodining), or any of an assortment of similar processes. In addition, stacked passivation techniques are often used for protecting aluminium. For example, chromating is often used as a sealant to a previously-anodized surface, to increase resistance to salt-water exposure of aluminium parts by nearly a factor of 2 versus simply relying on anodizing.
Iron based (ferrous) materials, including steel, may be somewhat protected by promoting oxidation ("rust") and then converting the oxidation to a metalophosphate by using phosphoric acid and further protected by surface coating. As the uncoated surface is water-soluble a preferred method is to form manganese or zinc compounds by a process commonly known as Parkerizing. Older, less-effective but chemically-similar electrochemical conversion coatings included bluing, also known as black oxide.
Nickel can be used for handling elemental fluorine, thanks to a passivation layer of nickel fluoride.
Terminology for assorted passivation processes
Bluing, also known as black oxide, and sometimes called browning when used in reference to historical processes dating from the 18th Century, is a passivation coating for the surfaces of iron and steel objects. It is one of the oldest passivation processes.
Newer, proprietary (and/or trademarked) processes for conversion coatings include Parkerized for passivating steel, dating to roughly 1912, and Alodine for passivating aluminium; both are trademarked processes and are now owned by Henkel Surface Technologies.
Chem film is any generic chromate conversion coating used to passivate aluminium. One such example is U.S. Patent 5,304,257. In general, however, chromate can also mean any of several chromate conversion coatings that can be applied to a much wider range of metals and alloys than just to aluminium. In recent years, chromate coatings have become less popular due to concerns over environmental pollution from using such processes.
Iridite is another trademarked name of a whole family of proprietary conversion coatings owned by MacDermid. A competing conversion coating used on aluminium, that somewhat ameliorates the environmental pollution concerns caused by chromate coatings, it often appears as a slightly yellowish coating, of roughly the same color as a yellow highlighting pen used to mark text on paper.
Rationale for passivating aluminium
Aluminium naturally forms an oxide almost immediately that protects it from further oxidation in many environments. This naturally-occurring oxide provides no protection during exposure to any saltwater spray environments, such as occurs in areas near bodies of saltwater. In such coastal environments, unprotected aluminium will turn white, corrode, and largely vanish over periods of exposure as short as a few years. The only way to prevent this from occurring is to use a more robust conversion coating on aluminium surfaces that will not be affected by the saltwater atmosphere. Alodine, Iridite, and chem film coatings can provide varying amounts of protection for aluminium surfaces.
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